Rotary disk oxygenator and heater



ROTARY DISK OXYGENA'I'OR AND HEATER Filed May 25, 1962 5 Sheets-Sheet 1Fig.

John E. Gala d0, J1:

[NV/:NTOR.

1965 J. E. -GALAJDAI, JR 3,211,148

ROTARY DISK OXYGENATOR AND HEATER Filed May 25, 1962 5 Sheets-Sheet 2Fig.4

John E. Gala d0, Jr.

INVENTOR.

Attorneys Oct. 12, 1965 Filed May 25, 1962 Fig.8

J. E. GALAJDA, JR

ROTARY DISK OXYGENATOR AND HEATER '5 Sheets-Sheet 3 Hill John E.Ga/ajaa, Jr.

INVENTOR.

BY @mmi Oct. 12, 1965 GALAJDA, JR 3,211,148

ROTARY DISK OXYGENA'IOR AND HEATER Filed May 25, 1962 5 Sheets-Sheet 4Ja/m E. Ga/ajaa, Jr.

INVENTOR.

ROTARY DISK OXYGENATOR AND HEATER Filed May 25, 1962 5 Sheets-Sheet 5Fig l0 Fig l/ 330 T Ja/m E Gala/d0 J1: 382 INVENTOR.

Mm BY ZWW'EMZEW United States Patent 3,211,148 ROTARY DESK OXYGENATORAND HEATER John E. Galajda, Jr., 35228 Center Ridge Road, NorthRidgeville, Ohio Filed May 25, 1962, Ser. No. 197,694 8 (Ilaims. (Cl.128-214) This invention comprises a novel and useful rotary diskoxygenator and heater and more particularly relates to a machine forquickly and safely oxygenating and heating large volumes of liquids andparticularly blood.

The invention disclosed and claimed herein relates to similar subjectmatter to that set forth in my prior application Serial No. 821,229,filed June 18, 1959, entitled Driver and Heater for Disk Oxygenator, nowPatent No. 3,053,229 of September 11, 1962, and constitutes improvementsthereover.

During the process of complete or partial circulatory by-pass of theheart and lungs during surgery for circulatory diseases, or as a supportto treatment of cardiopulmonary diseases, the rotating disk oxygenatorhas proved to be safe and valuable. However, the blood is subjected tocooling as it passes through the necessarily large tubing, pumps and theoxygenator unit. The oxygenator especially is a source of substantialcooling of the blood. Depending on blood flow rates, up to five litersof cold oxygen, carbon dioxide and anesthetic gases may pass through theoxygenator each minute. To offset this loss of heat, it was thoughtadvisable to pre-heat the gases passing into the oxygenator. Tests haveshown that although heat loss may be substantially reduced, this is apoor means for elevating or controlling blood temperature because of theheat diiferences in specific heats of the gases and liquid. There isalso an explosion hazard involved in the heating of anesthetic gasesmixed with oxygen.

Initial attempts to heat the blood in the oxygenator usually employed aresistance wire wound around the oxygenator bottle so that the blood iswarmed by conduct-ion through the glass side wall of the bottle and fromthe exterior surface of the liquid inwardly thereof. Like all methodsattempting to heat blood through the glass bottle, including infra-redheat, the surface available for heat transfer is smaller than thecooling surface presented by the disks in the relatively cooleratmosphere present Within the oxygenator and therefore the coolingeffect is greater than can be handled. The result is as follows: eitherthe temperature of the blood during the by-pass is considerably belownormal, or, excessive heating of the cylinder will maintain a normaltemperature of the blood but with excessive platelet destruction,hemolysis, and the collection of fibrin on the bottle.

This invention provides means by which to apply heat to the rotatingdisks in order to obtain multiple advantages. The first is that byheating the surface area of the disks, the area of heat exchange itselfis greatly increased. Further, it is possible to heat larger volumes ofblood more safely because of the increased surface area with a lowertemperature gradient. Secondly, since the heat transfer will take placeat the surface where gaseous exchange is taking place in the blood aswell as in the immersed portion of the disks, the problem of dissolvinggases coming out of physical solution with temperature rise isminimized.

Most other oxygenating systems warm the blood after the gaseous exchangehas taken place with the result that tiny air bubbles are produced inthe heater and may be carried through the circulatory system of thepatient with deleterious effects. The process of heating blood aftergaseous exchange has taken place and with the resulting change in thesolubility of the gases, especially carbon dioxide, results in shiftingpH. This problem can be rectified by the machine in accordance with thisinvention.

dilhlid Patented Oct. 12, I965 ice The convoluted disks of this machine,in order to give maximum surface area for heat transfer and gaseousexchange without creating undue turbulence and bubbling "are the par-tsof the machine which are heated.

The principal object of the invention is to provide a disk oxygenatorwhich is safer and more satisfactorily operative than prior diskoxygenators and made so by virtue of the construction of the heatingsystem of the disk oxygenator. The heat is preferably entrained in thesystem by means of the disks, and this may be the sole heating of theblood or may be used in combination with heat applied from the exteriorof the cylinder in which the disks are rotatable.

Another object of the invention is to provide an oxygenator system whichis so arranged as to always maintain all phases of the operation underthe control of the operator at one location so that the operation of theoxygenator may be monitored at all times by one person.

A further object of the invention is to effect heat exchange from acentral core or shaft upon which the disks are carried, through the hubsof the disks and radially outwardly therefrom across the entire surfacesof the disks. Thus the maximum temperature is at the axis of rotationand the heat is distributed radially therefrom by the structure of thedisks themselves.

Still another object of the invention is to provide an oxygenator inwhich the heating operation is effected by the circulation of hot waterthrough the central axis and hubs of the disks to thereby effect a veryrapid rate of heat input into the device.

A further object of the invention is to provide a device in accordancewith the foregoing object in which a rapid cooling of the liquids andgases within the enclosing chamber of the apparatus may be effected bypassing refrigerated fluids through the central axis and hubs of thedisks.

Still another object of the invention is to provide a heat exchangeapparatus whereby heat may be introduced into or withdrawn from a liquidthrough the agency of a series of disks rotatable therein and whereinthe enclosing casing may be sealed from the atmosphere to enable theapplication of any desired pressures from sub-atmospheric tosupra-atmospheric within the operating chamber of the device.

Still another object is to provide a device as set forth in thepreceding objects in which there is effected a uniform temperaturegradient throughout the area of the convo luted disks thereby securing amore even heating of the liquid.

An additional object, in compliance with the preceding objects is toprovide a device wherein the heating elements and/or the gas introducingmeans are compactly incorporated into the central axle of the devicewhich carries the disks.

These together with other objects and advantages which will becomesubsequently apparent, reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part thereof, whereinlike numerals refer to like parts throughout, and hi which:

FIGURE 1 is a view in vertical central section through a first suitableform of apparatus in accordance with this invention, arrows indicatingthe directions of flow of the fluids therethrough;

FIGURE 2 is a fragmentary end elevational view taken from the left endof FIGURE 1;

FIGURE 3 is a perspective view of a modified form of convoluted disk inaccordance with the invention;

FIGURE 4 is an enlarged sectional view of a portion of the arrangementof FIGURE 1 but showing the mounting and disposition of the convoluteddisks in the invention;

FIGURE 5 is a transverse sectional detail view taken upon an enlargedscale substantially upon the plane indicated by the section line 5--5 ofFIGURE 3 and showing the laminated construction of one of the convoluteddisks;

FIGURE 6 is a view in vertical central longitudinal section through aslightly modified second form of apparatus in accordance with theinvention, parts being broken away;

FIGURE 7 is a view in vertical transverse section taken substantiallyupon the plane indicated by the section line '7-7 of FIGURE 6;

FIGURE 8 is a vertical transverse sectional view taken substantiallyupon the plane indicated by the section line 88 of FIGURE 6 and showingthe structure and portion of a filter employed in the invention;

FIGURE 9 is a perspective view of the filter element, parts being brokenaway;

FIGURE 10 is a fragmentary view in vertical central longitudinal sectionof a third form of apparatus in accordance with this invention; and,

FIGURE 11 is a detail view in vertical longitudinal section of a furthermodified form of convoluted disk which may be used with any of theembodiments of the apparatus.

In the embodiments illustrated in the three forms of the inventiondisclosed in FIGURES 1, 6 and 10, a flat type of disk has beenillustrated in the interest of simplicity, but it is to be understoodthat either of the convoluted forms of disks shown in FIGURES 35 andFIGURE 11 is preferred as being a more efficient type of construction.

Referring first specifically to the embodiment of FIG- URES 1-5, it willbe observed that the oxygenator disclosed therein consists of a casingor tank which is sealed from the atmosphere and which may convenientlycomprise a cylindrical casing or body 10 of any suitable material butpreferably of a transparent nature and having removable end walls orclosure plates 12 and 14 secured to the open ends of the body and sealedthereto as by the reception of the ends of the body in circumferentiallyextending grooves or channels 16. Tensioning bolts 18, extending thelength of the body 10 and exteriorly thereof serve to securely clamp theend walls to the body and thus form the fluid tight tank or casing whichis sealed from the atmosphere and which thus provides a cylindricalliquid receiving and treating chamber therein.

The end wall 12 is provided with an internally threaded boss in which isreceived an externally threaded bushing 22 which constitutes a bearingor journal for the reduced and solid extremity 24 of the tubular axle orshaft 26 of a relatively good heat transmitting material. The other endof the shaft extends through the other end wall 14, and also extendsinto a housing indicated generally by the numeral 28. This housingconsists of an annular flange 30 constituting a diametrically enlargedouter end of a tubular boss 32 which is integral with the end wall 14.An internally threaded bore 34 is provided through this boss and endwall, and the other extremity of the shaft 26 extends through this boss,it being retained in a fluid tight sealed engagement therein as by meansof a stuffing box assembly 36 of a conventional design. A centrallyoutwardly dished cover plate 38 is detachably secured to the flange 30as by wing nuts 40 and provides a fluid collecting chamber 42 disposedwithin the housing 28 and which thus receives therein the open end ofthe shaft 26.

As will be observed from FIGURE 1, the shaft 26 is hollow to provide achamber or passage which terminates in the chamber 42 of the housing 23and which has its other end closely adjacent to the journal bearing 22.

Secured in but projecting axially from the hollow shaft 26 is a tubularor cylindrical member 44 disposed in concentric relation in the passagein the shaft 26 and fixedly secured to the wall 38 in any suitablemanner, not shown.

As will be further observed, the inwardly projecting end of the tubularmember 44 terminates in closely spaced relation to the inward or bottomWall of the passage in the shaft 26 so that it has free communicationwith this passage as shown by the arrows in FIGURE 1. The two concentricmembers, consisting of the tube 44 and the shaft 26, thus provide a pairof concentric passages, the innermost of which is indicated by thenumeral 46, while the numeral 48 designates the outermost thereof. Thesepassages comprise part of a means for circulating a heat exchangingfluid through the interior of the shaft 26.

It will be understood that the outermost end of the tube 44 extendsthrough and is preferably fixedly secured to the removable closure plate38 of the housing 28 for removement therewith, and has the end of aconduit 47 embracingly and removably secured thereto by means of which aheat exchange fluid of any suitable type has its inlet to the innerpassage 46. A threaded nipple 49 extending through the cover plate 38 ofthe housing 28 has a conduit removably and embracingly connected theretowhich constitutes the other fluid communicating passage of thecirculatory heating exchange system.

When it is desired to heat or cool the contents of the chamber withinthe casing 10, a heating fluid such as steam, hot water or the like orany suitable cooling fluid is delivered into the tube 44 as shown by thearrows, passes through the length of the inner passage 46 of the tube 44and then returns through the outer passage 48 of the shaft 26 whichopens continuously into the collection chamber 42 and from thence passesthrough the nipple 49 and conduit Sit back to the source of supply orany suitable place of discharge. Thus the conduits 46 and 50 comprisethe inlet and outlet means for circulating a heat exchanging liquid orfluid through the shaft 26.

When it is desired to employ the device for cooling or chilling thecontents of the casing 10, a refrigerant such as cool water or the likemay be circulated by the means previously described.

A body of liquid to be treated by the device is indicated by the numeral52 and is disposed and received within the chamber within the casing 10,being maintained at a desired liquid level such as that indicated at 54by suitable control valves, not shown, and by which the liquid isdelivered into the chamber through a fluid inlet means such as theconduit 56 and nipple 58 extending through the end wall 14, and isdischarged therefrom by means of the nipple 60 extending through the endwall 12 and which is connected to a fluid outlet conduit 62.

The casing is also provided with a gas inlet and gas outlet meansopening into the chamber within the casing 10 by means of which oxygenor other gases may be delivered into and discharged from the interior ofthe same for oxygenation of the liquid therein; or whereby any desiredpressure may be maintained upon the liquid; or whereby a subatmosphericpressure may be maintained thereon, it being understood that the inletand outlet means is connected to any suitable source of supply anddischarge and is operated by means of control valves of conventionaltype, not shown. For this purpose there is provided an inlet conduitsuch as that indicated at 64 which extends through the end wall 12, andan outlet conduit 66 which extends through the end wall 14. Theseconduits are preferably provided adjacent the top of the chamber withinthe casing or well above the liquid level 54 therein so that the gaseousmedium introduced into or withdrawn from the chamber will enter andleave the vapor space therein above the liquid level and will have acounter flow relative to the flow of liquid.

A previously mentioned, the arrangement is particularly adapted for theintroduction of oxygen into or the passage of oxygen through the chambertherein the casing 16 for the purpose of oxygenation of the liquid 52within which liquid may consist of blood taken from a patient and Whichblood is to be treated by various means prior to its return to thepatients body. Where a continuous circulation of oxygen or other gasthrough the chamber is desired, it is obvious that any suitable sourceof supply will be connected to the fluid inlet means 64 and such oxygeneither under pressure from a pump, or from a tank under pressure or fromthe atmosphere and at a controlled temperature may be inducted into thechamber, at a controlled rate as previously mentioned, and may bewithdrawn at a similar controlled rate through the outlet 66.

In order to effect a thorough and efiicent contact between the gases andliquid within the container, and in order to simultaneously impart heatthereto or to chill the same, as for example in order to maintain agiven temperature of the liquid during its passage through the chamber,there are provided a plurality of mixing and heating disks eachindicated generally by the numeral 70. In the form of disks illustratedin FIGURES 1, 6 and 10, the disks are centrally apertured for a snug butsliding engagement longitudinally upon the shaft 26, being separatedfrom each other by suitable annular spacer rings as at 72, and beingclamped into a rigidly secured assembly as by means of a clamping nut 74threaded on one end of the shaft and by a retaining member in the formof a ring 76 secured upon the other end of the shaft and abuttingagainst an adjusting nut 78 threaded in the bore 34 previouslymentioned.

In this manner the disks which may thus be readily removed or replacedor varied in number are rigidly clamped together in a closely spacedrelation with the hubs of the disks being in a good heat exchangerelation with the exterior of the shaft 26.

As will be observed from FIGURE 1, the liquid level 54 is maintained ata height to immerse any selected portion of the surface area of thedisks 70 in the liquid 52 with the remaining portion of the disksurfaces being exposed to the vapor space above the liquid level.Consequently, as the disks rotate upon rotation of the shaft, and thelatter is effected by any suitable means and source of power as by meansof a pulley 8t secured thereto, the rotating disks will lift liquid fromthe body of liquid 52, thereby coating the surface of the disks uponboth sides thereof with a thin liquid film and carry this coated surfaceor film into the vapor space within the chamber. Thus there is obtaineda highly effective contact area between the liquid and the gases withinthe chamber to effect the desired absorption of the gases by the liquid,as for example in order to oxygcnate blood or the like. Further, theinput of heat through the shaft will radiate outwardly along the disksfrom the central or hub portions thereof towards the periphery thereofand thus elfect a substantially uniform heating over a very largeeffective area of the liquid and gases within the chamber. In the caseof a coolant being circulated, it is of course evident that the reverseheat exchange relation will exist.

It will be observed that by this arrangement there is a minimumdisturbance or agitation of the liquids so as to avoid producingturbulence therein which in turn would tend to produce bubbles in theliquid. At the same time,

a maximum effective area of contact between the gas and liquid withinthe container is effected as well as a maximum rate of heat exchangetherebetween.

This apparatus is ideally adapted for use as a blood oxygenator forvarious types of medical equipment in view of the lack of turbulenceproduced in the blood during treatment, and the ability to obtain amaximum input of heat over a uniform and very great area of liquid andgas contact, without the danger of overheating the blood withdetrimental affects. Obviously, it is possible to vary the heating orcooling effect and the temperature maintained in the liquid within thedevice by controlling the rate of flow of the heat exchange medium inthe circulating passage system within the shaft 26.

A generally similar form of apparatus is disclosed in FIGURE 6 whereinthe same construction of casing me is provided with end walls 102 and104 sealed to the casing 1% in the manner previously described andretained clamped thereto as by the fastening bolts or tension members106. In this form of the invention there is likewise provided a gasinlet means 103 and a gase outlet means by means of which air or othergases may be supplied into the chamber within the casing 1% either bycirculating a gas therethrough for gas and liquid contact therein; forproducing a pressure above atmospheric therein, or for maintaining asubatmospheric pressure therein, and also, in some instances to effect aheat exchange with the liquid being treated. Also there is provided theliquid inlet means 112 and a liquid outlet means 114 provided in the twoend walls 194 and 102 respectively to thereby maintain a desired liquidlevel as at I16 within the device.

As in the preceding form of the invention there is likewise provided ahollow shaft formed of a good heat transmitting material and having oneend journaled in a suitable bearing bushing 122 provided in anexternally threaded tubular boss 124 formed in the end wall 104, with aheat exchange liquid outlet conduit means 126 being connected to thisboss as by means of a gland 128 to thus have continuous communicationwith the end of the hollow shaft 120.

The other end of the shaft extends through a suitable bearing 1%together with a packing gland or stuffing box assembly 132 formed in anaxially extending and enlarged boss 134 in the end wall 102. Secured tothe boss 134 is a housing or body 136 providing a chamber 138 betweenitself and the boss 134, the body being detachably secured as byfastening means Mt to the boss. A heat exchange fluid inlet meansindicated at 142 has communication with the interior of the chamber 138,and by means of a series of circumferentially spaced apertures or ports144 in the shaft 120 establishes communication with the interior of theshaft. Thus a heat exchange liquid, either heating or cooling, can becontinuously passed in one direction through the shaft to thereby heator cool the latter. The extremity of the shaft passes through a furtherpacking or stufiing box assembly as at 146 and is provided with a pulley148 or other means by which rotation of the shaft is obtained from anysuitable source of power, not shown.

As in the preceding embodiment, a plurality of disks I56 encircle theshaft in spaced relation thereon and are fixedly spaced from each otheras by means of spacer rings or collars 152 the assembly of disks andcollars being compressibly clamped together into a rigid assembly as bymeans of clamping nuts 154 and 156 threadedly engaged uponcorrespondingly externally threaded portions of the shaft. The disks andspacers are in good heat exchange relation with the exterior surface ofthe shaft.

The operation of this form of the invention is identical to thatpreviously described and a further description of the same is deemed tobe unnecessary.

A third form of apparatus, of generally similar construction andoperation, is illustrated in FIGURE 10. A cylindrical casing 300 isclamped between end plates 302 and 304 by the tension bolts 3% asdescribed in connection with the preceding embodiments. A hollow shaft303 of a good heat conducting material extends axially through thecasing 3th), being journaled therein by the bushings 310 and 312disposed in the end walls.

Liquid is maintained in the casing at a selected level 314 throughsuitable control of liquid flow through the liquid inlet means 316 andliquid outlet means 318. Gas or air inlet and outlet means 320 and 322respectively, each provided with conventional flow control means, notshown, introduce or exhaust air or other gases for the same purposes setforth in connection with the preceding embodiments.

A gas or air inlet housing 324 is detachably secured in embracingrelation upon a tubular boss 326 of the end plate 394 as by a fasteningmeans 328. The housing 324 surrounds the end of the shaft 303, having achamber 1? 330 supplied with gaseous fluid from any suitable source bythe fitting 332. This chamber 330 is continuously in communication bycross passages 334 with an axial bore or passage 335 in the shaft 3%.

The extremity of the shaft 3% passes through sealing elements 336 and338 in the housing 324 on opposite walls of the chamber 330 and projectsbeyond the housing 324 for connection to any suitable driving means, notshown.

The other end of the shaft 308 is enlarged and has an enlarged bore orchamber 34% therein with which the bore 335 communicates. Received inthe bore 348 is a sheet metal tube or sleeve 342 of a good heatconductive material. The inner end 346 of the tube 342 terminates inspaced relation to the inner or bottom wall of the chamber 343 intowhich the bore 335 enters providing a chamber 348. The latter serves toprovide a continuous connection between the exterior of the tube 342 andthe bore 335 for a purpose to be subsequently apparent.

Received within the tube 342 and entering from a housing 350 whichcovers the open other end thereof are the electrical conductors 352 ofany conventional electric resistance heating elements 354.

The exterior surface of the shaft 3% along any desired length thereofhas longitudinal channels ass which are in continuous communication withthe chamber 343 and the bore 340 about the exterior of the tube 342.Fixedly but removably secured upon the shaft 308 is an assem bly ofdisks 360 and spacer collars 362, the latter having projecting spacerlugs 364 on one face thereof. A clamping nut 366 threaded on the shaft368 clamps the assembly of disks and spacers in rigidly compressiverelation as against the bushing 31%.

In this manner, gaseous fluids introduced from the members 332, 330,334, 335, 348 and 356 are uniformly diffused and vented into the vaporspace above the liquid level 314 in the casing 301) and also areuniformly distributed in an intimate liquid and vapor contact with theliquid film carried by each disk 360. Thus the effective area of gas andliquid contact is greatly increased and rendered more efficient.

In some instances the electrical heating element 354 may of course bereplaced by other heating or cooling mediums of the characterhereinbefore set forth.

However, although the relatively flat or straight disks '70, 150 or 360of the three preceding embodiments may in some instances besatisfactorily employed, it is pre ferred to employ a convoluted type ofdisk in the assemblages of FIGURES l, 6 or 10, such types of disk beingshown in detail in FIGURES 3-5 and 11. struction of FIGURES 3-5, eachdisk designated generally by the numeral 160 is of a laminatedconstruction and also is of a convoluted configuration. Thus, as shownbest in FIGURE 5, the disk consists of a central or medially disposedplate or sheet of material 162 of a relatively high heat exchangecharacteristic, copper, aluminum or silver being satisfactory for thispurpose. Further, there are provided a pair of outer layers or sheets ofmaterial as at 164 and 166 bonded in any suitable manner to the oppositesides of the medial layer 162. These outer sheets are preferably of amaterial possessing to a high degree the characteristic of beingnon-wettable and of relatively poor thermal conductivity in order that arelatively thin disk will conduct heat uniformly over its surface forthe particular liquid with which the device is to be operated. For thispurpose the outer sheets may be of nickel, chrome or of suitable plasticmaterials such as nylon.

As previously mentioned, the preferred form of disk 160 is convoluted inits contour. Thus there are provided a plurality of circumferentiallyextending ridges 158 which project upon opposite sides of the disks asshown in FIG- URES 4 and 5, there being corresponding depressions orvalleys between these ridges as shown at 1'70. As will be perceived fromFIGURES 4 and 5, the ridges on one In the con- 8 side of the disk areaccompanied by corresponding valleys on the other side thereof so that aseries of disks may be nested with respect to each other as shown inFIGURE 4.

An important feature of this invention resides in the selecting of thenecessary critical proportions of curvatures of the surface of the diskbetween the valleys and ridges of the convolutions and also the relativedepth and width of such ridges and valleys so as to produce the mosteffective spacing of the disks and of their nested convolutions andridges as shown in FIGURE 4. This spacing is so chosen as to prevent thesurface tension of the liquid tending to bridge the gap between adjacentdisks and thus insure that each disk will be coated with a film of theliquid to be heated thereby independently of the coating of the otherdisks. Further, the rate of curvature of the disks is such that takinginto consideration the viscosity of the liquid, the latter will not fillthe valleys of the convolutions and thereby reduce the surface area forgas exchange. The rate of curvature also determines the spacing of thedisks.

For convenience of illustration, FIGURE 4 shows the hub portions 172 ofeach disk being disposed between and clamped between adjacent spacers orcollars 174 upon the shaft 26. However, it will be understood that inthe interest of better heat exchange relation it may be preferred toform the hubs of the disks laterally enlarged so that they willthemselves provide the necessary spacing elements therebetween.

In the flow of heat radially outwardly in a disk from the hub toward thedisk periphery, a disk of uniform thickness is well known to be coolerthan its hub portion. In order to overcome this disadvantage andmaintain a more uniform temperature over the entire surface of the disk,a contour such as that shown in FIGURE 11 is employed.

Here a disk 380 is corrugated in the same manner as described inconnection with the disk 160 of FIGURES 3 and 4 and likewise may belaminated as set forth in FIGURE 5. However, the disk has a relativelywide hub 382 where the disk is mounted in good heat exchange relationupon the central shaft and is of a progressively narrowing thickness asit approaches its rim. The rate of narrowing is in accordance with theheat flow gradient of the particular material employed so that the rateof heat emission or absorption by the disk over its surface will producea uniform temperature thereon.

In each form of the invention as shown in FIGURES 1, 6 and 10, there isprovided a filter element of a construction shown in FIGURES 8 and 9.The filter element bearing the same numerals in both FIGURES 1 and 6,serves the very important function of preventing any emboli, clots ordebris from passing into the general circulation system of the patient.By the arrangement of the filter unit within the oxygenator separate andadditional priming with blood is rendered unnecessary, saving both timeand blood.

For convenience, the filter unit is disposed immediately adjacent to theoutlet end plates 12 or 102 of FIGURES l. and 6 respectively, beingretained in place in any desired suitable manner.

The filtering device comprises a pair of rings 200 and 2 02 of a vinylplastic or other suitable material Whose oute peripheries may be snuglyand frictionally gripped by the wall of the casing 10 and 100. Acrossthe lower portion of each ring is an integral fiat bar 204 which dividesthe area of the ring into a relatively large upper opening 206 and asmaller lower opening 208.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. A blood heat exchange apparatus comprising a tank having a chamberfor receiving blood therein and closed from the atmosphere, a rotaryshaft in said cham ber, driving means connected to said shaft foreffecting rotation thereof, conduit means connected to said shaft forcirculating therethrough a heat exchanging fluid, a plurality of spaceddisks adapted to be at least partially immersed in the blood in saidchamber and having hubs fixedly secured to said shaft in good heatexchange relation, said disks being convoluted and disposed in a spacedbut nested relation, said conduit means comprising a housing encirclingone end of said shaft and forming a chamber thereabout, said shaftincluding therein a pair of longitudinally extending passages, saidpassages having communication with each other within one end of saidshaft, the other end of one passage being connected to said housing andinlet means and outlet means for a heating fluid connected to saidhousing and to the other end of the other of said passages.

2. The combination of claim 1 wherein said housing and said heatingfluid inlet and outlet means are disposed upon the exterior of saidtank.

3. The combination of claim 2 wherein said tank has an end wall and saidhousing is supported thereby.

4. An oxygenator heat exchange gas and liquid contact apparatuscomprising a horizontally elongated tank having a liquid receivingchamber therein sealed from the atmosphere, said tank having end wallsdefining opposite ends of said chamber, means including a liquid inletand a liquid outlet in opposite end walls for maintaining an adjustableliquid level in said chamber, means including an inlet and anoutlet inopposite end walls for effecting a flow of oxygen through said chamberabove said liquid level and in counterflow to the liquid flow, a shaftin said chamber having its opposite ends journaled in and extendingthrough said end walls and disposed for rotation about a horizontal axisnormally located above said liquid level, a plurality of disks removablymounted in longitudinally spaced relation upon said shaft, each diskbeing in good heat exchange relation with said shaft, said disks beingadapted to have their lower portions immersed in and their upperportions disposed above said maintained liquid level, means forreleasably axially com pressing and clamping said disks into a rigidassembly and fixedly upon said shaft, drive means rotating said shaft,said shaft having a bore opening from one end of said shaft andextending substantially the entire length of said disk assembly, astationary tube carried by an end wall and concentrically disposed inand extending substantially the entire length of said bore and means atthe open end of said tube for establishing communication respectivelywith said bore and tube and for supplying a heat exchange fluid to andfor withdrawing it from said shaft.

5. The combination of claim 4 wherein one of said heat exchange fluidsupplying and withdrawing means comprises a boss on the exterior of anend wall, a housing secured to said boss and defining a collectionchamber therewith into which said shaft bore discharges, said 10 shaftbeing journaled in said boss and said tube being carried by saidhousing.

6. The combination of claim 4 wherein said disks are of a progressivelynarrowing width from their centers to their peripheries suflicient tomaintain a substantially uniform temperature over their surface areas.

'7. An oxygenator and heat exchange gas and liquid contact apparatuscomprising a horizontally elongated tank having a liquid receivingchamber therein sealed from the atmosphere, said tank having end wallsdefining opposite ends of said chamber, means including a liquid inletand a liquid outlet in opposite end Walls for maintaining an adjustableliquid level in said chamber, means including an inlet and an outlet inopposite end walls for effecting a flow of oxygen through said chamberabove said liquid level and in counterfiow to the liquid flow, a shaftin said chamber having its opposite ends journaled in and extendingthrough said end walls and disposed for rotation about a horizontal axislocated above said liquid level, a plurality of disks removably mountedin longitudinally spaced relation upon said shaft, each disk being ingood heat exchange relation with said shaft, means for releasablyaxially compressing and clamping said disks into a rigid assembly andfixedly upon said shaft, drive means rotating said shaft, said shafthaving a bore therein, means for introducing a heat exchange means intosaid bore from one end of said shaft, means for introducing oxygen intosaid bore from the other end of said shaft and passages in said shaftdischarging oxygen from said bore into said chamber above the liquidlevel therein.

8. The combination of claim 7 wherein said passages discharge into thespaces between each pair of adjacent disks whereby to contact the liquidon said adjacent disks with oxygen from said bore.

References Cited by the Examiner UNITED STATES PATENTS 254,003 2/82Gontard 261-92 998,020 7/11 Mabee 26l-87 1,166,139 12/15 Marwedel 165-921,879,140 9/32 Edwards l--146 1,895,287 1/33 Lambert -1 -446 1,995,3023/35 Goldstein 1282l4 2,680,007 6/54 Arbuckle 165-86 3,065,748 11/62Senning et .al. 128-214 3,074,401 1/63 Friedman et a1 1282l4 FOREIGNPATENTS 408,016 4/34 Great Britain.

OTHER REFERENCES Mendelsohn et al.: Management of the Patient DuringOpen Heart Surgery, from Surgery, vol. 45, No. 6, June 1959, pp. 949-53.

RICHARD A. GAUDET, Primary Examiner. JORDAN FRANKLIN, Examiner.

1. A BLOOD HEAT EXCHANGE APPARATUS COMPRISING A TANK HAVING A CHAMBERFOR RECEIVING BLOOD THEREIN AND CLOSED FROM THE ATMOSPHERE, A ROTARYSHAFT IN SAID CHAMBER, DRIVING MEANS CONNECTED TO SAID SHAFT FOREFFECTING ROTATION THEREOF, CONDUIT MEANS CONNECTED TO SAID SHAFT FORCIRCULATING THERETHROUGH A HEAT EXCHANGING FLUID, A PLURALITY OF SPACEDDISKS ADAPTED TO BE AT LEAST PARTIALLY IMMERSED IN THE BLOOD IN SAIDCHAMBER AND HAVING HUBS FIXEDLY SECURED TO SAID SHAFT IN GOOD HEATEXCHANGE RELATION, SAID DISKS BEING CONVOLUTED AND DISPOSED IN A SPACEDBUT NESTED RELATION, SAID CONDUIT MEANS COMPRISING A HOUSING ENCIRCLINGONE END OF SAID SHAFT AND FORMING A CHAMBER THEREABOUT, SAID SHAFTINCLUDING THEREIN A PAIR OF LONGITUDINALLY EXTENDING PASSAGES, SAIDPASSAGES HAVING COMMUNICATION WITH EACH OTHER WITHIN ONE END OF SAIDSHAFT, THE OTHER END OF ONE PASSAGE BEING CONNECTED TO SAID HOUSING ANDINLET MEANS AND OUTLET MEANS FOR A HEATING FLUID CONNECTED TO SAIDHOUSING AND TO THE OTHER END OF THE OTHER OF SAID PASSAGES.